Effect of Hydrogen Charging Time on Tensile Properties and Fracture Behavior of QP980 Steel

doi:10.12068/j.issn.1005-3026.2026.20240129

Abstract

Abstract:

The effect of hydrogen charging time on the hydrogen embrittlement （HE） of the multiphase microstructure of QP980 steel was studied by electrochemical hydrogen charging and slow strain rate tensile （SSRT） tests. The stress-strain curve shows that the tensile strength and elongation decrease significantly with the increase of hydrogen charging time， but the presence of hydrogen does not affect the work hardening rate before fracture. The fracture morphology analysis shows that in the absence of hydrogen， the fracture mode at the center of the specimen is a mixed dimple and quasi-cleavage， and the edge region exhibits a dimple fracture morphology. After hydrogen charging， the mixed fracture zone of the specimen expands， and the unit facet size of quasi-cleavage increases with prolonged hydrogen charging time. Observations of secondary cracks and microstructure revealed that at lower hydrogen concentrations， the phase interfaces between ferrite and martensite served as the primary sites for crack initiation. These cracks propagated along the ferrite-martensite interfaces but were blunted by the ferrite phase， resulting in microvoid-coalescence type cracks. This indicates that the hydrogen-enhanced localized plasticity （HELP） mechanism was the dominant hydrogen embrittlement mechanism under these conditions. When hydrogen concentration is high， the cracks transform into hairline cracks and pass through the matrix ferrite structure， indicating that the hydrogen-enhanced decohesion （HEDE） is the dominant mechanism.

Key words: QP980 steel, hydrogen charging, hydrogen-induced crack, slow strain rate tensile, hydrogen embrittlement mechanism

CLC Number:

TG 142.1

Xin-yi RUAN, Jing-jing YIN, Zhi-yuan CHANG, Liang-yun LAN. Effect of Hydrogen Charging Time on Tensile Properties and Fracture Behavior of QP980 Steel[J]. Journal of Northeastern University(Natural Science), 2026, 47(1): 115-122.

Figures/Tables 8

Fig.1 SEM microstructure of QP980 steel

Fig.2 Observation location of secondary cracks

Fig.3 SSRT test results of QP980 steel

Table 1 Specimen’s tensile strength and

变量	损失率
变量	HC-2h	HC-12h	HC-24h	HC-24h/24h
抗拉强度	13.1	27.6	31.4	4.9
延伸率	52.5	75.3	76.2	0.0

Fig.4 Surface fracture morphology of specimens under different hydrogen charging time

Fig.5 Secondary cracks and microstructure of central section near fracture surface

Fig.6 Crack morphology of matrix under different hydrogen charging time

Fig.7 Hydrogen-induced fracture process and HE mechanism of QP980 steel under different hydrogen charging time

References 20

[1]	Alves P H O M， Lima M S F， Raabe D， et al. Laser beam welding of dual-phase DP1000 steel［J］. Journal of Materials Processing Technology， 2018， 252： 498-510.
[2]	Guo W， Wan Z D， Peng P， et al. Microstructure and mechanical properties of fiber laser welded QP980 steel ［J］. Journal of Materials Processing Technology， 2018， 256： 229-238.
[3]	de Moor E， Lacroix S， Clarke A J， et al. Effect of retained austenite stabilized via quench and partitioning on the strain hardening of martensitic steels［J］. Metallurgical and Materials Transactions A， 2008， 39： 2586-2595.
[4]	Bleck W， Guo X F， Ma Y. The TRIP effect and its application in cold formable sheet steels［J］. Steel Research International， 2017， 88（10）： 1700218.
[5]	Huang J N， Tang Z Y， Ding H， et al. Combining a novel cyclic pre-quenching and two-stage heat treatment in a low-alloyed TRIP-aided steel to significantly enhance mechanical properties through microstructural refinement［J］. Materials Science and Engineering： A， 2019， 764： 138231.
[6]	朱旭. 基于TRIP效应的第3代先进高强汽车用钢氢脆机制的研究［D］. 上海：上海交通大学， 2016.
	Zhu Xu. An investigation into the hydrogen embrittlement mechanism in the 3rd generation advanced high strength automotive steels employing TRIP effect ［D］. Shanghai： Shanghai Jiao Tong University， 2016.
[7]	Chen D Y， Wang L M， Wang C Z，et al. Finite element based improvement of a light truck design to optimize crashworthiness［J］. International Journal of Automotive Technology， 2015， 16（1）： 39-49.
[8]	祁豆豆，林万明，李双寿. 淬火-分配工艺对高强钢疲劳失效的影响［J］. 中国冶金， 2017， 27（6）： 24-29.
	Qi Dou-dou， Lin Wan-ming， Li Shuang-shou. Effect of quenching-partitioning process on fatigue failure of high strength steel［J］. China Metallurgy， 2017， 27（6）： 24-29.
[9]	Zhu X， Li W， Zhao H S， et al. Effects of cryogenic and tempered treatment on the hydrogen embrittlement susceptibility of TRIP-780 steels［J］. International Journal of Hydrogen Energy， 2013， 38（25）： 10694-10703.
[10]	Loidl M， Kolk O， Veith S， et al. Characterization of hydrogen embrittlement in automotive advanced high strength steels［J］. Materialwissenschaft und Werkstofftechnik， 2011， 42（12）： 1105-1110.
[11]	王金荣，许强，逯志强，等. 980 MPa级汽车用钢氢致延迟断裂性能［J］. 电镀与精饰， 2021， 43（1）： 41-46.
	Wang Jin-rong， Xu Qiang， Lu Zhi-qiang， et al. Hydrogen induced delayed fracture of 980 MPa grade automotive steel ［J］. Plating and Finishing， 2021， 43（1）： 41-46.
[12]	陈亚军，邝霜，赵征志. 先进高强度汽车用钢氢致延迟断裂研究进展［J］. 钢铁研究学报， 2020， 32（4）： 265-272.
	Chen Ya-jun， Kuang Shuang， Zhao Zheng-zhi. Study status of hydrogen induced delayed fracture of advanced high strength automotive steel［J］. Journal of Iron and Steel Research， 2020， 32（4）： 265-272.
[13]	Speer J， Matlock D K， de Cooman B C， et al. Carbon partitioning into austenite after martensite transformation［J］. Acta Materialia， 2003， 51（9）： 2611-2622.
[14]	黄发，周庆军. 高强钢的氢致延迟断裂行为研究进展［J］. 宝钢技术， 2015（3）： 11-16.
	Huang Fa， Zhou Qing-jun. Progress and perspectives of hydrogen induced delayed fracture of high strength steels［J］. Baosteel Technology， 2015（3）： 11-16.
[15]	Zhou Y， Wu W J， Li J X. Simultaneous improvement of hydrogen embrittlement resistance and tensile strength of quenching and partitioning steel through dense multiple interfaces［J］. International Journal of Hydrogen Energy， 2024， 58： 1372–1385.
[16]	Wang Z， Luo Z C， Huang M X. Revealing hydrogen-induced delayed fracture in ferrite-containing quenching and partitioning steels ［J］. Materialia， 2018， 4： 260-267.
[17]	Kim H J， Shin G， Park J， et al. Pre-strain and hydrogen charging effect on the plastic and fracture behavior of quenching and partitioning （Q&P） steel［J］. Acta Materialia， 2024， 263： 119524.
[18]	Huang S， Hui H， Peng J. Prediction of hydrogen-assisted fracture under coexistence of hydrogen-enhanced plasticity and decohesion［J］. International Journal of Hydrogen Energy， 2023， 48（94）： 36987-37000.
[19]	Nagao A， Smith C D， Dadfarnia M， et al. The role of hydrogen in hydrogen embrittlement fracture of lath martensitic steel［J］. Acta Materialia， 2012， 60（13/14）： 5182-5189.
[20]	Kim H J， Lee M G. Analysis of hydrogen trapping behaviour in plastically deformed quenching and partitioning steel in relation to microstructure evolution by phase transformation［J］. Journal of Alloys and Compounds， 2022， 904： 164018.